I have an MX-850 with an MRF-350. It has been working fine until this morning, when we tried to turn the TVs on. I just changed the batteries on the remote, and when I attempt to make an action, the signal icon lights up on the remote. However, neither the "status" light on the base station, nor the "RF" light on the received light up. I've unplugged the base station, and the "status" light flashes three times when I plug it back in. Any thoughts?
Check the connection between the RFX-250 antenna and the MRF-350 base. You might even want to try using the phoenix connector on the MRF-350 instead of the plug. You also need to confirm that the "Power" indicator is on, both with the MRF-350 and the RFX-250. It's possible that the RF transmitter on the MX-850 went out, but it's more likely that it's the RFX-250 that's the problem.
Try pointing the remote directly at the components and see if that works (i.e. take the MRF out of the picture).
This will not necessarily "take the MRF out of the picture." All devices in the program could be set to "RF" and not "IR & RF", meaning that pointing the remote directly at the equipment would not do anything.